Human neurocysticercosis, the infection of the nervous system by the larvae of Taenia solium, is a major cause of epileptic seizures and other neurologic morbidity worldwide. The diagnosis and treatment of neurocysticercosis have been considerably improved in recent years. This improvement includes identification and sequencing of specific antigens and development of new assays for laboratory diagnosis, recognition of the frequency and significance of edema around old, calcified cysts (associated to symptomatic episodes), results of a randomized blinded control treatment trial on treatment efficacy for intraparenchymal disease showing a clinical benefit of decreased seizures, and a much better assessment of the frequency and spectrum of cerebrovascular complications. These advances now permit a much better integration of clinical, serologic, and imaging data for diagnosis and therapeutic purposes.

A multi-test strip dotblot immunoassay for the diagnosis of typhoid fever, scrub typhus, murine typhus, dengue virus infection and leptospirosis was evaluated in Thai adults presenting to hospital with acute, undifferentiated fever. The kit gave multiple positive test results in 33 of 36 patients with defined infections and was therefore not a useful admission diagnostic tool.

Experimental infection of marmoset monkeys (Callithrix jacchus) with Leptospira interrogans serovar Copenhageni showed microscopic patterns of tissue reactions comparable to those seen in the severe forms of human leptospirosis, including intra-alveolar hemorrhage. The most impressive microscopic changes were seen in the lung and kidney of animals killed at days 6 and 12 after inoculation. There were extensive and irregular areas of hemorrhage predominating around main bronchial branches or diffusely spread to the pulmonary parenchyma, as well as severe tubulointerstitial nephritis. Antibody response detected by the microscopic agglutination test was quantitatively similar to those seen in humans and paralleled severity of tissue lesions. The distribution of leptospires or antigenic debris in infected tissues was observed by immunofluorescence and confocal laser scanning microscopy. Large numbers of typical leptospires were seen in the lumen of proximal renal tubules. Positive reactions showing antigenic debris were closely associated with sites of tissue damage.

Among populations living in areas endemic for malaria, repeated parasite exposure leads to a gradual increase in protective immunity to the disease. In contrast, this immunity is assumed to disappear after several years of non-exposure. This study was designed to investigate long-term immunity in subjects removed from the risk of exposure. Plasmodium falciparum malaria attacks occurring after short trips to sub-Saharan Africa were compared between 99 European patients and 252 African immigrants who had been resident in Europe for at least four years. Relative to the European patients, those originating from Africa had lower mean ± SD parasite densities (0.8 ± 1.5/100 red blood cells versus 1.4 ± 2.8/100 red blood cells; P = 0.007), less frequent severe disease (4.4% versus 15.2%; P = 0.0005), accelerated parasite clearance and defervescence, and higher levels of antibodies to P. falciparum. These results suggest the persistence of acquired immunity to P. falciparum malaria after several years of non-exposure in African immigrants.

Logistic, economic, and technical factors limit rapid access to microscopic confirmation of malaria in many tropical countries, including India. The occurrence of high-grade fever and three deaths during the hot summer months in some forest migrants created an emergency situation in Jabalpur in central India. A cheap and rapid malaria test, Paracheck® Pf, was tested in this group of migrants in parallel with microscopy. The indigenous population at the site of occupational activities of these migrants approximately 250 km from Jabalpur was also screened by both methods. The results of this field investigation are very encouraging. Among migrants, the test had a sensitivity of 100% and a specificity of 67%. The positive and negative predictive values were 94% and 100%, respectively. Among indigenous population, the corresponding values were 100%, 97.3%, 98.4%, and 100%, respectively, indicating the usefulness of test as a diagnostic tool for providing on-site confirmation of symptomatic diagnosis of Plasmodium falciparum malaria.

A 37-year-old man was diagnosed as being infected with human immunodeficiency virus (HIV), tuberculosis (TB), tuberculoma of the brain, and visceral leishmaniasis (VL) at the Rajendra Memorial Institute of Medical Sciences in Bihar, India. He had taken anti-tuberculosis therapy (ATT) for two and a half months and had episodes of convulsions with loss of consciousness, tongue bites, and incontinence of urine. The results of a neurologic examination were normal except for a left plantar extensor. He was positive for both HIV-I (confirmed by Western blot) and VL (confirmed by splenic aspirate). Treatment was initiated with amphotericin B lipid complex, a four-drug regimen (rifampicin, isoniazid, ethambutol, and pyrazinamide) of ATT, highly active antiretroviral therapy, anti-convulsants, and other supportive therapies. A repeat computed tomography scan of the brain showed the disappearance of the lesion followed by gliosis. After six months, he was also cured of VL. The triad of infections (HIV, VL, and TB) is a real threat in Bihar as an emerging combination of diseases of public health importance. Keeping these facts in mind, efforts to develop simple and cost effective diagnostic techniques coupled with affordable therapeutic facilities are urgently needed in developing countries.

To investigate the spread of human immunodeficiency virus (HIV) and other sexually transmitted viruses, two serosurveys (the first in 1999 among 56 adults and the second in 2001 among 351 adults) were conducted in remote villages of the southwestern part of Papua New Guinea. Only one individual was positive for antibodies to HIV. In 2001, the seroprevalence of human herpes virus 8 (HHV-8) was 32.2%, and the seroprevalence of herpes simplex virus type 2 (HSV-2) was 27.4%. Both prevalence rates increased with age, and were lower in the villages near the Bensbach River. The seropositivity of HSV-2 was independently correlated with HHV-8 infection. Our data show that the inhabitants of the southwestern region of Papua New Guinea currently experience an extremely low circulation of HIV. However, the high prevalence of infectious agents that can be sexually transmitted, such as HSV-2 and to a lesser extent HHV-8, indicates the presence of behavioral patterns that may facilitate the spread of HIV in this area of currently low endemicity.

The prevalence of Toxoplasma gondii in indigenous Brazilian tribes with different degrees of acculturation was studied in the Enawenê-Nawê, an isolated tribe, in the state of Mato Grosso, the Waiãpi, with intermittent non-Indian contacts, in the state of Amapá, and the Tiriyó, with constant non-Indian contacts, in the state of Pará. An IgG–enzyme-linked immunosorbent assay (IgG-ELISA) or an IgG/IgM–indirect immunofluorescence antibody (IFA) assay were performed for the detection of antibodies to T. gondii in 2000–2001. Both assays showed that the Tiriyó had the lowest crude seroprevalence (55.6%), the Enawenê-Nawê the highest crude seroprevalence (80.4%), and the Waiãpi an intermediate crude seroprevalence (59.6%). The age-adjusted prevalence (95% confidence intervals) values for the Tiriyó, Enawenê-Nawê, and Waiãpi were 57.3% (53.4, 61.1%), 78.8% (72.2, 85.7%), and 57.7% (52.5, 62.9%), respectively. Contact with non-Indians probably did not influence the prevalence of the infection. However, differential contact with soil-harboring oocysts from wild felines may be responsible for the various seroprevalences in the different tribes.

In August 2002, two cases of hantavirus pulmonary syndrome (HPS) were confirmed in Mineros and Concepción, within the Santa Cruz Department of Bolivia. Extensive alteration of the native ecosystem, from dense forest to pasture or sugarcane, had occurred in both regions. An ecologic assessment of reservoir species associated with the human disease identified a single hantavirus antibody-positive Oligoryzomys microtis from Mineros and three hantavirus antibody-positive Calomys callosus from Concepción. In Mineros, the virus from the O. microtis was 90% similar to sequences published for Río Mamoré virus. Viral nucleotide sequences from two C. callosus were 87–88% similar to the sequence of Laguna Negra virus. The viral sequence from the C. callosus was 99% identical to viral sequences obtained from the HPS patient in this area, implicating C. callosus as the host and Laguna Negra virus as the agent responsible for the HPS case near Concepción.

In sub-Saharan Africa, the etiology of anemia in early childhood is complex and multifactorial. Three community-based cross-sectional surveys were used to determine the prevalence and severity of anemia. Regression methods were used to compare mean hemoglobin (Hb) concentrations across covariate levels to identify children at risk of low Hb levels in an area with intense malaria transmission. In a random sample of 2,774 children < 36 months old, the prevalence of anemia (Hb < 11g/dL) was 76.1% and 71%, respectively, in villages without and with insecticide-treated bed nets (ITNs); severe-moderate anemia (Hb < 7 g/dL) was observed in 11% (non-ITN) and 8.3% (ITN). The prevalence of anemia, high-density malaria parasitemia (21.7%), microcytosis (34.9%), underweight (21.9%), and diarrhea (54.8%) increased rapidly from age three months onwards and remained high until 35 months of age. Multivariate analyses showed that family size, history of fever, pale body, general body weakness, diarrhea, soil-eating, concurrent fever, stunting, and malaria parasitemia were associated with mean Hb levels. Prevention of severe anemia should start early in infancy and include a combination of micronutrient supplementation, malaria control, and possibly interventions against diarrheal illness.

A prospective study of dengue fever (DF) and dengue hemorrhagic fever (DHF) was conducted in a cohort of adult volunteers from two textile factories located in West Java, Indonesia. Volunteers in the cohort were bled every three months and were actively followed for the occurrence of dengue (DEN) disease. The first two years of the study showed an incidence of symptomatic DEN disease of 18 cases per 1,000 person-years and an estimated asymptomatic/ mild infection rate of 56 cases per 1,000 person-years in areas of high disease transmission. In areas where no symptomatic cases were detected, the incidence of asymptomatic or mild infection was 8 cases per 1,000 person-years. Dengue-2 virus was the predominant serotype identified, but all four serotypes were detected among the cohort. Four cases of DHF and one case of dengue shock syndrome (DSS) were identified. Three of the four DHF cases were due to DEN-3 virus. The one DSS case occurred in the setting of a prior DEN-2 virus infection, followed by a secondary infection with DEN-1 virus. To our knowledge, this is the first report of a longitudinal cohort study of naturally acquired DF and DHF in adults.

From September 2000 to June 2003, a community-based program for dengue control using local predacious copepods of the genus Mesocyclops was conducted in three rural communes in the central Vietnam provinces of Quang Nam, Quang Ngai, and Khanh Hoa. Post-project, three subsequent entomologic surveys were conducted until March 2004. The number of households and residents in the communes were 5,913 and 27,167, respectively, and dengue notification rates for these communes from 1996 were as high as 2,418.5 per 100,000 persons. Following knowledge, attitude, and practice evaluations, surveys of water storage containers indicated that Mesocyclops spp. already occurred in 3–17% and that large tanks up to 2,000 liters, 130–300-liter jars, wells, and some 220-liter metal drums were the most productive habitats for Aedes aegypti. With technical support, the programs were driven by communal management committees, health collaborators, schoolteachers, and pupils. From quantitative estimates of the standing crop of third and fourth instars from 100 households, Ae. aegypti were reduced by approximately 90% by year 1, 92.3–98.6% by year 2, and Ae. aegypti immature forms had been eliminated from two of three communes by June 2003. Similarly, from resting adult collections from 100 households, densities were reduced to 0–1 per commune. By March 2004, two communes with no larvae had small numbers but the third was negative; one adult was collected in each of two communes while one became negative. Absolute estimates of third and fourth instars at the three intervention communes and one left untreated had significant correlations (P = 0.009−< 0.001) with numbers of adults aspirated from inside houses on each of 15 survey periods. By year 1, the incidence of dengue disease in the treated communes was reduced by 76.7% compared with non-intervention communes within the same districts, and no dengue was evident in 2002 and 2003, compared with 112.8 and 14.4 cases per 100,000 at district level. Since we had similar success in northern Vietnam from 1998 to 2000, this study demonstrates that this control model is broadly acceptable and achievable at community level but vigilance is required post-project to prevent reinfestation.

ChimeriVax™-dengue (DEN) viruses are live attenuated vaccine candidates. They are constructed by replacing the premembrane (prM) and envelope (E) genes of the yellow fever (YF) 17D virus vaccine with the corresponding genes from wild-type DEN viruses (serotypes 1–4) isolated from humans. In this study, the growth kinetics of ChimeriVax™-DEN1-4 and parent viruses (wild-type DEN-1-4 and YF 17D) were assessed in human myeloid dendritic cells (DCs) and in three hepatic cell lines (HepG2, Huh7, and THLE-3). In DC, ChimeriVax™-DEN-1-4 showed similar growth kinetics to their parent viruses, wild-type DEN virus (propagated in Vero cells), or YF 17D virus (peak titers ~3–4.5 log10 plaque-forming units (PFU)/mL at 48–72 hours post-infection). Parent wild-type DEN-1-4 viruses derived from C6/36 mosquito cells did not show any growth at a multiplicity of infection of 0.1 in DCs, except for DEN-2 virus, which grew to a modest titer of 2.5 log10 PFU/mL at 48 hours post-infection. ChimeriVax™-DEN1-4 grew to significantly lower titers (2–5 log10 PFU/mL) than YF 17D virus in hepatic cell lines THLE-3 and HepG2, but not in Huh7 cells. These experiments suggest that ChimeriVax™-DEN1-4 viruses replicate similarly to YF-VAX® in DCs, but at a lower level than YF 17D virus in hepatic cell lines. The lack of growth of chimeric viruses in human hepatic cells suggests that these viruses may be less hepatotropic than YF 17D virus vaccine in humans.

Cathepsin L1, a cysteine protease secreted by the gastrodermis of juvenile and adult Fasciola gigantica, was expressed in Escherichia coli as a calmodulin binding peptide fusion protein with a molecular mass of approximately 35 kD. The recombinant cathepsin L1 (rCTL1) was tested for its antigenic potential in a cystatin capture enzyme-linked immunosorbent assay (ELISA) to diagnose human fascioliasis. The ELISA plates were sensitized with chicken egg cystatin and incubated with bacterial lysates containing the recombinant protein before the standard ELISA procedures were performed. Analysis of the sera of 13 patients infected with F. gigantica (group 1), 204 patients with other parasitic infections (group 2), 32 cholangiocarcinoma patients (group 3), and 42 healthy controls (group 4) showed that the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of this ELISA using rCTL1 were 100%, 98.92%, 98.97%, 81.25%, and 100%, respectively. These results indicate that this assay has high sensitivity and specificity in the diagnosis of human fascioliasis. In addition, we have produced sufficient amounts of antigen for use in diagnosis.

The surveillance of prevalent Leishmania and sand fly species in endemic areas is important for prediction of the risk and expansion of leishmaniasis. In this study, we developed a polymerase chain reaction (PCR)-based method for detection of Leishmania minicircle DNA within individual sand flies. Using this method, we detected minicircle DNA in 6 (3.3%) of 183 sand flies, while 5 (3.5%) of 143 were positive for Leishmania promastigotes in the same areas by microscopic examination. The species were identified as Leishmania (Leishmania) mexicana by nucleotide sequencing of the cytochrome b gene. Additionally, all the Leishmania-positive sand flies were identified as Lutzomyia ayacuchensis by the restriction enzyme digestion of the PCR-amplified 18S ribosomal RNA gene fragments. Since this combined method is relatively easy and can process a large number of samples, it will be a powerful tool for the rapid identification of prevalent sand fly and Leishmania species as well as monitoring the infection rate in sand fly populations in endemic areas.

Sand flies inject saliva into the mammalian host when probing for a blood meal. Understanding the initial vertebrate reactions against sand fly saliva is important for possible interventions because these insects transmit diseases to humans and other animals. Little is known of these reactions to New World sand flies. Repeated exposure of BALB/c mice to Lutzomyia longipalpis bites leads to local inflammatory cell infiltration comprised of neutrophils, macrophages, and eosinophils. Total IgG and IgG1 antibodies react predominantly with three major protein bands (45, 44, and 16 kD) of the insect saliva by Western blot. The injection of immune serum previously incubated with salivary gland homogenate induced an early infiltration with neutrophils and macrophages, suggesting the participation of immune complexes in triggering inflammation.

The observation of avian mortality associated with West Nile virus (WNV) infection has become a hallmark epidemiologic feature in the recent emergence of this pathogen in Israel and North America. To determine if phenotypic differences exist among different WNV isolates, we exposed house sparrows (Passer domesticus) to low passage, lineage 1 WNV strains from North America (NY99), Kenya (KEN), and Australia (KUN; also known as Kunjin virus). House sparrows inoculated with the NY99 and KEN strains experienced similar mortality rates and viremia profiles. The KUN strain elicited significantly lower-titered viremia when compared with the other strains and induced no mortality. This study suggests that natural mortality in house sparrows due to Old World strains of WNV may be occurring where the KEN strain occurs.

To evaluate the prevalence of toxocariasis in children in Jaboatão dos Guararapes, Pernambuco in northeastern Brazil, 215 serum samples were examined by an enzyme-linked immunosorbent assay (ELISA) using a recombinant Toxocara canis antigen. In the ELISA, 26 (12.1%) of 215 subjects were positive. In a dot-blot assay using 53 of 215 serum samples, the diagnostic results correlated with those obtained by the ELISA. Moreover, it has been confirmed that the recombinant T. canis antigen was highly specific for toxocariasis by ELISA using serum samples positive for antibody to Ascaris lumbricoides. Considering the specificity of the recombinant antigen to toxocariasis, the ELISA or dot-blot assay using the recombinant T. canis antigen is recommended in tropical and sub-tropical regions where various parasitic infections are commonly endemic.